Yes, if you choose to trust and believe the veterinarian that is treating your dog.
Plus all the research and trials done by the dog food company that employs veterinary nutritionists.
When a dog is sick, optimum nutrition is not the primary goal. That is why prescription dog food is not recommended for healthy dogs.
However, if you would prefer to focus on one ingredient that you don’t understand the purpose of, and disregard all the other potential benefits that a therapeutic diet can provide.
So be it.
Feather meal is actually more expensive than chicken meal because breaking it down to amino acid level is a costly process. (info obtained from)
https://www.forbes.com/sites/marcbabej/2013/05/29/dog-food-made-from-feathers-a-win-win-for-royal-canin/#75f7fda8456f
